U.S. patent number 3,953,862 [Application Number 05/536,606] was granted by the patent office on 1976-04-27 for printing head device for an ink jet printer.
This patent grant is currently assigned to Facit Aktiebolag. Invention is credited to Jan Roger Amberntsson, Roger Ingemar Andersson, Stig Bertil Sultan.
United States Patent |
3,953,862 |
Amberntsson , et
al. |
April 27, 1976 |
Printing head device for an ink jet printer
Abstract
A printing head for an ink jet printer in which a liquid
reservoir is operatively associated therewith. The liquid reservoir
is provided with an air inlet opening having a filter which permits
the passage of air but prevents liquid flow thereby preventing the
leakage of liquid out of the reservoir upon the agitation of the
liquid within the reservoir.
Inventors: |
Amberntsson; Jan Roger
(Angered, SW), Andersson; Roger Ingemar (Angered,
SW), Sultan; Stig Bertil (Floda, SW) |
Assignee: |
Facit Aktiebolag (Atvidaberg,
SW)
|
Family
ID: |
20319526 |
Appl.
No.: |
05/536,606 |
Filed: |
December 26, 1974 |
Foreign Application Priority Data
|
|
|
|
|
Dec 28, 1973 [SW] |
|
|
7317524 |
|
Current U.S.
Class: |
347/87 |
Current CPC
Class: |
B41J
2/175 (20130101) |
Current International
Class: |
B41J
2/175 (20060101); G01D 015/16 () |
Field of
Search: |
;346/140 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Hartary; Joseph W.
Attorney, Agent or Firm: Miller; Alfred E.
Claims
What is claimed is:
1. In a printing head device for an ink jet printer the improvement
comprising: a liquid reservoir for said ink supply associated with
said printing head and movable therewith and provided with an air
inlet opening, and a filter in said opening being constituted of a
material that permits the passage of air but prevents the flow of
liquid therethrough.
2. A liquid reservoir as claimed in claim 1 wherein said filter is
constituted of a non-wetting material.
3. A liquid reservoir as claimed in claim 2 wherein said filter is
constituted of a polytetrafluoroethylene.
4. A liquid reservoir as claimed in claim 1 wherein both said air
inlet opening and said filter are disposed above the normal liquid
level in said reservoir.
5. In a printing head device for an ink jet printer the improvement
comprising: a liquid reservoir for said ink supply associated with
said printing head, said reservoir being provided with a top
opening, and a cover for said opening which is at least partly
constituted of a filter material, said filter material being of the
non-wetting type that permits the passage of air but prevents the
flow of liquid therethrough.
Description
BACKGROUND OF THE INVENTION
Ink jet printing devices that are known have arrangements in which,
for example, printing ink is conveyed from a liquid reservoir to a
movable printing head by means of comparatively long flexible
hoses. It is quite difficult to replace the long hoses with a
liquid reservoir that follows the movement of the printing head
because the reservoir is subject to considerable acceleration and
deceleration due to the rather rapid movements of the printing
head. Consequently, the rapid movements of the liquid in the
reservoir cause liquid agitation so that on one hand air is mixed
into the liquid and on the other hand the liquid can leak out of
the air inlet opening to the reservoir. Moreover, the air mixed
with the liquid in the reservoir further causes foam to be formed
on the liquid surface which, in turn, causes liquid to leak through
the air inlet opening.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an ink jet
printing head with an associated liquid reservoir in which the
latter is provided with an air inlet opening having a filter that
permits the passage of air to the interior of the reservoir
receptacle but prevents the flow of liquid out of the
receptacle.
It is another object of the present invention to provide a filter
for the inlet opening of the reservoir which is constituted of a
non-wetting material.
A further object of the present invention is an alternate
construction of the reservoir having a cover for the open top of
the reservoir that is entirely of a non-wetting filter
material.
The invention will now be more fully described with reference to
the accompanying drawings as follows:
FIG. 1 is a diagrammatic view of the printing head device for an
ink jet printer constructed in accordance with the teachings of the
present invention.
FIG. 2 is an enlarged side elevational view, partly in section, of
the details of construction of the printing head and its associated
reservoir, and
FIG. 3 is an enlarged sectional view of an alternate embodiment of
the reservoir shown in FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As seen in FIG. 1, an ink jet printer assembly is provided with a
housing 10 in which is located a printing head 11 and a liquid
reservoir 12. The reservoir 12 is preferably integral with the
printing head 11. Each of the pump chambers of the printing head 11
are provided with a pumping means such as a piezoelectric crystal
13. The pumping means each have an ink channel 14 opening into a
respective capillary nozzle 15. The liquid ink is propelled out of
the nozzles 15 by means of the pumping means on the print medium,
for example a paper tape 16 which is unwound from the supply roller
16. The tape 16 passes between the press roller 19 and the
associated rotary roller 17 and thereafter through paper guide 20
and finally wound on take-up reel 21.
The printing head 11 is secured to a support 22 which in turn is
slidably mounted on a shaft 23. Furthermore, the printing head can
be moved transversely along the roller 17 by means of a driving
device (not shown).
Referring now to FIG. 2 in which the printing head 11 and
associated reservoir 12 is shown in greater detail, the liquid 24
can be conveyed to the various pump chambers in the printing head
by means of the enlarged bore 25 in the bottom section 26 of the
reservoir and through conduit 27 and connecting channels 28. An
annular support member 29 is shown located in the bore 25 with the
filter element 30 resting thereon. The filter 30 is constituted of
porous material so that its capillaries, when filled with liquid,
prevent air from entering the conduit 27.
As seen in FIG. 2, the top of the reservoir is provided with a
threaded opening 31 through which liquid is supplied to the
reservoir 12. A plug 32 is threaded into the opening 31 and has an
air inlet channel 33. The bottom of the plug 32 is provided with a
countersunk bore 32a having a filter 34 therein. Thus, air passing
through the channel 33 into the reservoir has to pass through the
filter 34. The latter is constituted of a non-wetting material, for
example polytetrafluoroethylene which has a multiplicity of narrow
channels.
Since the filter material is non-wetting the liquid cannot pass
through the channels to the air inlet channel 33 but air can pass
the other way through the filter 34 without any blockage.
Therefore, the present construction prevents liquid from leaking
out through channel 33 in the case of liquid foaming as the result
of rapid movements of the printing liquid 24.
Referring now to the construction shown in FIG. 3 in which the open
top reservoir 12 is illustrated as provided with a closing cover 35
composed of a non-wetting material and corresponding to the filter
34 of FIG. 2. Numerous channels can be made in the entire surface
of the cover 35 for the purpose of admitting air to the reservoir
12.
It should be noted that for both the constructions of FIG. 2 and
FIG. 3 the non-wetting filter is placed above the normal liquid
level in the reservoir 12.
The present liquid reservoir for an ink jet printing head includes
a filter which successfully allows the passage of air but prevents
the flow of liquid therethrough.
* * * * *